Since perivascular pericytes have ability to produce increased amounts of fibronectin as a reaction to insults (Mandarino et al., 1993; Makihara et al., 2015) and fibronectin have a possible role in regulating endothelial permeability to inflammatory cells (Sava et al., 2015), we evaluated the effect of MS sera and CBX incubation on fibronectin levels. The gene discussed is FN1; the disease is myeloid sarcoma.